From patchwork Sat Mar 26 17:28:46 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 64502 Delivered-To: patch@linaro.org Received: by 10.112.199.169 with SMTP id jl9csp709586lbc; Sat, 26 Mar 2016 10:30:35 -0700 (PDT) X-Received: by 10.98.8.74 with SMTP id c71mr30486139pfd.155.1459013407425; Sat, 26 Mar 2016 10:30:07 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id f63si2362197pfj.137.2016.03.26.10.30.07; Sat, 26 Mar 2016 10:30:07 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753598AbcCZR3y (ORCPT + 3 others); Sat, 26 Mar 2016 13:29:54 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:40505 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752150AbcCZR3w (ORCPT ); Sat, 26 Mar 2016 13:29:52 -0400 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u2QHTYD5016349 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 26 Mar 2016 17:29:35 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserv0022.oracle.com (8.13.8/8.13.8) with ESMTP id u2QHTY75011359 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sat, 26 Mar 2016 17:29:34 GMT Received: from abhmp0014.oracle.com (abhmp0014.oracle.com [141.146.116.20]) by userv0121.oracle.com (8.13.8/8.13.8) with ESMTP id u2QHTXEQ012067; Sat, 26 Mar 2016 17:29:33 GMT Received: from localhost.localdomain (/73.159.178.34) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 26 Mar 2016 10:29:33 -0700 From: Sasha Levin To: stable@vger.kernel.org, stable-commits@vger.kernel.org Cc: Yang Shi , Will Deacon , He Kuang , Sasha Levin Subject: [added to the 4.1 stable tree] arm64: replace read_lock to rcu lock in call_break_hook Date: Sat, 26 Mar 2016 13:28:46 -0400 Message-Id: <1459013330-15318-42-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1459013330-15318-1-git-send-email-sasha.levin@oracle.com> References: <1459013330-15318-1-git-send-email-sasha.levin@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yang Shi This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html =============== [ Upstream commit 62c6c61adbc623cdacf74b8f29c278e539060c48 ] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 0, irqs_disabled(): 128, pid: 342, name: perf 1 lock held by perf/342: #0: (break_hook_lock){+.+...}, at: [] call_break_hook+0x34/0xd0 irq event stamp: 62224 hardirqs last enabled at (62223): [] __call_rcu.constprop.59+0x104/0x270 hardirqs last disabled at (62224): [] vprintk_emit+0x68/0x640 softirqs last enabled at (0): [] copy_process.part.8+0x428/0x17f8 softirqs last disabled at (0): [< (null)>] (null) CPU: 0 PID: 342 Comm: perf Not tainted 4.1.6-rt5 #4 Hardware name: linux,dummy-virt (DT) Call trace: [] dump_backtrace+0x0/0x128 [] show_stack+0x20/0x30 [] dump_stack+0x7c/0xa0 [] ___might_sleep+0x174/0x260 [] __rt_spin_lock+0x28/0x40 [] rt_read_lock+0x60/0x80 [] call_break_hook+0x30/0xd0 [] brk_handler+0x30/0x98 [] do_debug_exception+0x50/0xb8 Exception stack(0xffffffc00514fe30 to 0xffffffc00514ff50) fe20: 00000000 00000000 c1594680 0000007f fe40: ffffffff ffffffff 92063940 0000007f 0550dcd8 ffffffc0 00000000 00000000 fe60: 0514fe70 ffffffc0 000be1f8 ffffffc0 0514feb0 ffffffc0 0008948c ffffffc0 fe80: 00000004 00000000 0514fed0 ffffffc0 ffffffff ffffffff 9282a948 0000007f fea0: 00000000 00000000 9282b708 0000007f c1592820 0000007f 00083914 ffffffc0 fec0: 00000000 00000000 00000010 00000000 00000064 00000000 00000001 00000000 fee0: 005101e0 00000000 c1594680 0000007f c1594740 0000007f ffffffd8 ffffff80 ff00: 00000000 00000000 00000000 00000000 c1594770 0000007f c1594770 0000007f ff20: 00665e10 00000000 7f7f7f7f 7f7f7f7f 01010101 01010101 00000000 00000000 ff40: 928e4cc0 0000007f 91ff11e8 0000007f call_break_hook is called in atomic context (hard irq disabled), so replace the sleepable lock to rcu lock, replace relevant list operations to rcu version and call synchronize_rcu() in unregister_break_hook(). And, replace write lock to spinlock in {un}register_break_hook. Signed-off-by: Yang Shi Signed-off-by: Will Deacon Signed-off-by: He Kuang Signed-off-by: Sasha Levin --- arch/arm64/kernel/debug-monitors.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index b056369..70654d84 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -271,20 +271,21 @@ static int single_step_handler(unsigned long addr, unsigned int esr, * Use reader/writer locks instead of plain spinlock. */ static LIST_HEAD(break_hook); -static DEFINE_RWLOCK(break_hook_lock); +static DEFINE_SPINLOCK(break_hook_lock); void register_break_hook(struct break_hook *hook) { - write_lock(&break_hook_lock); - list_add(&hook->node, &break_hook); - write_unlock(&break_hook_lock); + spin_lock(&break_hook_lock); + list_add_rcu(&hook->node, &break_hook); + spin_unlock(&break_hook_lock); } void unregister_break_hook(struct break_hook *hook) { - write_lock(&break_hook_lock); - list_del(&hook->node); - write_unlock(&break_hook_lock); + spin_lock(&break_hook_lock); + list_del_rcu(&hook->node); + spin_unlock(&break_hook_lock); + synchronize_rcu(); } static int call_break_hook(struct pt_regs *regs, unsigned int esr) @@ -292,11 +293,11 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr) struct break_hook *hook; int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL; - read_lock(&break_hook_lock); - list_for_each_entry(hook, &break_hook, node) + rcu_read_lock(); + list_for_each_entry_rcu(hook, &break_hook, node) if ((esr & hook->esr_mask) == hook->esr_val) fn = hook->fn; - read_unlock(&break_hook_lock); + rcu_read_unlock(); return fn ? fn(regs, esr) : DBG_HOOK_ERROR; }